A conventional tension adjusting device generally includes multiple sets of adjusting units which are required to be restored precisely. However, there are some inherent problems which are not overcome by the existed tension adjusting device.
The present invention intends to provide a restoring device of the tension adjusting device of sewing machines, and the restoring device includes a restoring arm and a restoring member on two sides of the main part and the two restoring arm and member apply forces on the pressing board which evenly applies to the restoring sets so as to achieve the desired functions.